The statements in this section merely provide background information related to the present disclosure. Accordingly, such statements are not intended to constitute an admission of prior art.
Wire harnesses are used in a multitude of applications to electrically connect devices and systems. Wire harnesses can be used in automotive, appliances, aeronautical, computer, or other similar applications. Quality of crimped wire bundles is critical especially for circuitry used for signal processing and other applications where maximum allowable resistance of the crimp is measured in milli-ohms. A wire bundle includes a plurality of individual metallic wire strands. Each of the wire strands are in direct metal to metal contact with each other and collectively serve to transmit current along the wire bundle. The wire bundle is typically wrapped or coated with an insulator.
Wire harnesses frequently involve a plurality of wire bundles connected together wherein each wire bundle includes at least two ends. Each end of a wire bundle needs to establish an electrical connection with another object. The other object can be a device, an inline connector, a computerized module, or another wire bundle. Electrical connectors are known in the art, wherein a single wire bundle or a plurality of wire bundles are able to be plugged into another connector. Such connectors are frequently fool-proofed, wherein they can only be connected in one orientation, such that only the desired electrical connections can be made.
While electrical connectors are frequently molded plastic structures, the wire bundles that go into the electrical connectors need a conductive interface with wire surfaces or conductive circuitry leading into the mating electrical connector. Wire bundles can be connected to a conductive interface embodied as a crimped end interface or a crimped end. Such a crimped end or terminal can project from the wire bundle as a pin or male connector or a slot or female connector. A terminal interconnection system involves a male terminal inserted into a female terminal. On any terminal, the crimped end frequently includes a pair of tabs or a barrel that are folded over and pressed tightly or crimped around an exposed metal tip of the associated wire bundle. The crimped end can also include a similar crimp connection to an insulator or polymer coating of the wire bundle around the metal wire bundle. Such an insulation crimp can provide strain relief. In one exemplary configuration, a water proof grommet known in the art can be placed between the crimped end and the wire insulator, such that a water proof connection to a connector can be subsequently made. Wire bundles can also be connected to terminals with another method, such as insulation displacement termination or welding. Both the crimped connection from the crimped end to the exposed metal wire bundle and to the insulator are both important to the long term performance and reliability of the wire bundle. A bad crimp or a failed crimp can lead to intermittent or failed connection of the electrical wire bundle to the intended circuitry.
Testing of crimped wire connections and terminal interconnection systems for reliability and performance of the connection and/or quality of the crimp or crimps frequently includes durability testing, wherein the wire bundle is connected and resistance as a measure of the electrical connection is monitored over a long period of time. Temperature and humidity may be varied over the test period to simulate environmental effects upon the terminals, the wire bundle and the crimped portions.